Conventionally, a vehicle electric power distribution adjusting device configured to prevent degradation of functions due to shortage of supply of electric power has been suggested (see, for example, Japanese Laid-Open Patent Application Publication No. 5-77680). This vehicle electric power distribution adjusting device detects a demanded electric power level of each electric demand equipment unit so as to calculate a sum of the demanded electric powers. When the sum of the demanded electric powers exceeds an allowable electric power of an electric power supply side, electrical power consumption of the electric demand equipment having a low priority is limited.
However, in the above-mentioned related art, the electric power distributed to each electrical loading is adjusted based on a preset order of priority after the demanded electric power of each electrical loading is detected. Accordingly, as the demanded electric power of the electric demand equipment units having a high priority is larger so that the demanded electric power exceeds the allowable electric power of the electric power supply side, electric power supply to other electric demand equipment units is more difficult.